When the Bajorans begin to fill the conduits with anethezine gas O'Brien claims he would have thought of that himself. Well why didn't he? If he had filled the docking ring with the stuff as soon as the Bajorans arrived, the attack would have bene stopped then and there.

Factoid :

Stephen Macht was once under consideration for the role of Captain Picard!

Plotline

While Sisko and his officers use guerrila tactics against the Circle on DS9, Kira and Dax must rush to the Chamber of Ministers with evidence that the Circle is a front for the Cardassians. But powerful forces are determined to stop them at any cost.